Licia Verde

1. Licia Verde University of Pennsylvania www.physics.upenn.edu/~lverde Connecting cosmology to fundamental physics

2. Dark matter (Spergel talk) Neutrinos (Spergel talk) Inflation Dark energy Testing fundamental physics by looking up at the sky is not new The interplay between astrophysics and fundamental physics has already produced spectacular findings (e.g. the solar neutrino problem) Cosmology has entered the precision era very recently Cosmological data* can be used to test fundamental physics 4 Areas *For now, CMB is the cleanest probe we have

3. Cosmology has a standard model:What have we learned? If you see the glass half empty: When things do not make sense… invoke a scalar field… If you see the glass half full: Outline: Precision Cosmology: examples Inflation: what have we learned, prospects for the future Dark energy: what we have learned, prospects for the future Conclusions

4. COBE 1992 Bennett et al. 1996 WMAP 2003 Bennett et al 2003

6. Today 2dFGRS

7. SDSS here SDSS

8. Hot and cold spots  Tiny ripples in density  seeds of galaxies WMAP view of the primordial fireball Detailed statistical properties of these ripples tell us a lot about the Universe Bond Efstathiou 1987

9. Hot and cold spots  Tiny ripples in density  seeds of galaxies WMAP view of the primordial fireball Detailed statistical properties of these ripples tell us a lot about the Universe

10. What’s going on Matter overdensities compress cosmic fluids through gravity Photons (tightly coupled to the baryons) counteract this Acoustic oscillations set in Sound speed is high (photon/baryon high) cs=c/3 1/2 Sound horizon cst defines a maximum size Phase correlation:structures of a given size start oscillating together Damping: photons free streaming, finite thickness of LSS Work of Peebles & Yu, Sunyaev & Zeldovich ‘70

11. Status in early 2003 (From Hinshaw et al 2003)

12. Approximation to the state of the art now 100 2 10 1000 WMAP1 + CBI + ACBAR+ CBI05+ Boomerang 05+VSA

13. Approximation to the state of the art now 100 2 10 1000 WMAP1 + CBI + ACBAR+ CBI05+ Boomerang 05+VSA

14. 1 deg compression Acoustic peaks (extrema) rarefaction compression Primordial ripples Fundamental mode

15. compression Rarefaction… etc Potential wells baryons Geometry Primordial ripples +primordial perturbations Fundamental mode Jungman, Kamionkowski, Kosowsky, Spergel, 1996

16. Generation of CMB polarization • Temperature quadrupole at the surface of last scatter generates polarization. From Wayne Hu YES, there is also reionization Rees 68, Coulson et al ‘94 ….. Hu& White 97(pedagogical) Potential hill Potential well

17. Polarization for density perturbation • Radial (tangential) pattern around hot (cold) spots.

18. Image from J. Rhul.

19. Image from J. Rhul.

20. E and B modes polarization E polarization from scalar, vector and tensor modes B polarization only from (vector) tensor modes Kamionkowski, Kosowsky, Stebbings 1997, Zaldarriga & Seljak 1997

21. ?

22. V() H ~ const  Inflation Solves cosmological problems (Horizon, flatness). Cosmological perturbations arise from quantum fluctuations, evolve classically. Guth (1981), Linde (1982), Albrecht & Steinhardt (1982), Sato (1981), Mukhanov & Chibisov (1981), Hawking (1982), Guth & Pi (1982), Starobinsky (1982), J. Bardeen, P.J. Steinhardt, M. Turner (1983), Mukhanov et al. 1992), Parker (1969), Birrell and Davies (1982)

23. Horizon problem Flatness problem Structure Problem

24. WMAP Consistent with Simplest Inflationary Models Causal Seed model (Durrer et al. 2002) • Flat universe: Wtot = 1.02 ± 0.02 • Gaussianity: -58 < ƒNL < 134 • Power Spectrum spectral index nearly scale-invariant: ns = 0.99 ± 0.04 (WMAP only) • Adiabatic initial conditions • Superhorizon fluctuations (TE anticorrelations) Primordial Isocurvature i.c. WMAP TE data in bins of l=10 (Peiris et al. 2003) Primordial Adiabatic i.c. Hu & Sujiyama 1995 Zaldarriaga & Harari 1995 Spergel & Zaldarriaga 1997

25. Gravity Waves in the CMB Inflation produces two types of perturbations: in the energy density ( as seen in TT) and in the gravitational field (gravity waves). Unlike temperature anisotropy, CMB polarization anisotropy can discriminate between scalar modes (density perturbations) and tensor modes (gravity waves). (r=tensor to scalar ratio) • Primordial B-mode anisotropy • Inflation-generated gravity waves (tensor modes) polarize CMB • (Kamionkowski & Kosowski 1998) • A “smoking gun” of inflation => holy grail of CMB measurements • At least an order of magnitude smaller than E-mode polarization

26. Seeing (indirectly) z>>1100 Information about the shape of the inflaton potential is enclosed in the shape and amplitude of the primordial power spectrum of the perturbations. Information about the energy scale of inflation (the height of the potential) can be obtained by the addition of B modes polarization amplitude. In general the observational constraints of Nefold>50 requires the potential to be flat (not every scalar field can be the inflaton). But detailed measurements of the shape of the power spectrum can rule in or out different potentials. For example: Kahler inflation towards the KKLT minimum, or for multi-field other minima

27. Primordial power spectrum=A kn slope Amplitude of the power law A ln P(k) (convention dependent) ! ln k

28. Running of the spectral index generalize Taylor expand >0 =0 d ln P/d ln k <0 pivot

29. “Generic” predictions of single field slow roll models (hybrid) Each point is a “viable” slow roll model, able to sustain inflation for sufficient e-foldings to make the universe flat. Monte Carlo simulations following Kinney (2002) and Easther and Kinney (2002) (Peiris et al. 2003)

30. WMAP Constraints on Inflationary Models (From Peiris et al. 2003) Negative curvature (e.g.: new inflation) Small positive curvature (e.g.: chaotic inflation, extended inflation) Intermediate positive curvature Large positive curvature (e.g.: hybrid inflation) Recommended: For given model, sit on that point and run likelihood analysis (may need to integrate mode equation directly). lf4 model: Not in such a good shape….. See also Kinney et al. (2003)

31. Leach & Liddle 03 Barger et al 03 CMB only With LSS

32. The inflaton potential Kinney et al 2003

33. Prospects for the future: A: Better shape of the primordial power spectrum: WMAP II (more data, and breaking degeneracies) Probing smaller scales? Planck ACT Large-scale structure?

34. ACT: The Atacama Cosmology Telescope Columbia U Mass Princeton Penn Toronto CUNY Haverford The CMB can also be used to measure large-scale structure www.hep.upenn.edu/act P.I. Lyman Page

35. Region of the sky covered by ACT Courtesy of Carlos Hernandez-Monteagudo Strip of 2.5 degrees in width

36. B: Prospects for B Modes measurements

37. Dark Energy SN 1A (Riess et al 04) DARK ENERGY…. CMB+ H prior (HST Key project) CMB (WMAP ext ‘03) LSS (2dF Verde et al 02)

38. What have Supernovae observations shown? From Riess et al 04

39. W ?

40. WMAP With new SN data (Riess et al. 2004)

41. WMAP With new SN data (Riess et al. 2004) H prior from HST key project

42. With 2dF (LSS) But, why constant?

43. Assuming a flat Universe…. Baryon oscill. SDSS Eisenstein et al. 05 CTIO +CMB+SN Jarvis et al 05 (75 sq degrees, no redshifts) + CFHTLS Sembloni et al 05 (3 sq degrees) But, why w constant? Why flatness?

44. Constraints on QUINTESSENCE Galaxy surveys Keeping flatness and power law P(k)

45. THE SYMPTOMS Or OBSERVATIONAL EFFECTS of DARK ENERGY Recession velocity vs brightness of standard candles: dL(z) CMB acoustic peaks: Da to last scattering Da to zsurvey LSS: perturbations amplitude today, to be compared with CMB (or Matter density today)

46. HOW TO MAKE A DIAGNOSIS? Any modification of gravity of the form of f( R ) can be written as a quintessence model for a(t) This degeneracy is lifted when considering the growth of structure Effort in determining what the growth of structure is in a given Dark Energy model! combination of approaches!

47. COMPLEMENTARITY IS THE KEY! The questions we want to ask: Is it a cosmological constant? A rolling scalar field? A fluid? Is it a w= -1? w(z)? Is it a breakdown of GR at horizon scales? Example: Measurements of the growth of cosmological structures will help to disentangle the two cases. Things could be “going wrong” in other ways Backreaction… For not mentioning: control of systematics!

48. We can “measure” dark energy because of its effects on the expansion history of the universe and the growth of structure SN: measure dL CMB: A and ISW  a(t) LSS or LENSING: g(z) or r(z)  a(t) AGES: H(z)  a(t)

49. MEASURING DARK ENERGY: future prospects Bonds CD’s CMB angular-size distance (improvement?) Combined with acoustic BAO in galaxy distribution At 0<z<2 (or so…) SZ +WL masses Growth of structure: clusters surveys with optical follow up X-rays Not to scale Supernovae KSZ ISW The shape of the red envelope: i.e. relative ages of galaxies, i.e. H(z) See eg. Jimenez et al 03, Simon et al 05 ……. Highly volatile mutual funds Gamma-Ray bursts

50. Conclusions: Precision cosmology is here Cosmology and particle physics are now asking the same questions (but addressing them in complementary ways) We can test fundamental physics by looking up at the sky Inflationary models can be ruled in/out (watch this space) Dark energy: for now it is consistent with a cosmological constant Rolling scalar field/constant/modification of gravity? Cosmological observations have discriminative power. The next few years (days) will be exciting